Chrome Version (from the about:version page): 51.0.2704.84 64bit
Is this the most recent version: yes
OS + version: Goobuntu trusty (Linux 4.2.0-36-generic #42~14.04.1-Ubuntu SMP Fri May 13 17:27:22 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux)
CPU architecture (32-bit / 64-bit): 64 bit
Window manager: Cinnamon, HW accelerated
URLs (if relevant): N/A
Behavior in Linux Firefox: N/A
Behavior in Windows Chrome (if you have access to it): N/A

Laptop model and config: Lenovo ThinkPad X1 Carbon 3rd gen, Intel HD 5500, 2560×1440 native resolution (also happened using 2 external HD monitors)

What steps will reproduce the problem?
Unfortunately no reliable reproduction steps, but in all instances (happened three times in one month), the operations leading up the the issue were:
(1) Have a running Chrome session with multiple windows / tabs (perhaps 10-15 tabs total)
(2) Trigger a cinnamon desktop animation:
    * switch workspace
    * open Alt+Tab switcher
    * click on link in Gmail Chrome app which opens a tab in a Chrome window on a different desktop, which in turn triggers switch-workspace animation

What is the expected result?
The Cinnamon animation plays normally, and performs the associated action (switch workspace, show different window).

What happens instead?
The entire UI freezes, often mid-animation or right at the start of it playing. The mouse pointer still moves, and all processes including Chrome still seem to remain alive (e.g. music playing in same Chrome session continues to play). The machine can be rebooted gracefully by revoking keyboard focus from X (Alt+Prtscr+R) and then hitting Ctrl+Alt+Del. Switching to virtual terminals is not possible. The screen only updates once Ctrl+Alt+Del has been pressed and the "Goobuntu" shutdown animation starts playing (four blinking dots). Chrome shuts down cleanly and doesn't generate a crash report, and restores the session after reboot without any error messages.


Please provide any additional information below. Attach a screenshot
and backtrace if possible.
Filed bug 28729190 with the Goobuntu team, who asked me to file here. You can find system logs and more details there. Please let me know what additional I can gather e.g. from Chrome (and share here).